The philosopher known for his contributions during the Enlightenment period is Immanuel Kant. His work, particularly in the area of epistemology and metaphysics, encouraged rigorous examination of human reason and ethics. Kant's "Critique of Pure Reason" challenged the rationalist and empiricist traditions, advocating for a synthesis of the two. His moral philosophy, which emphasized duty and the categorical imperative, laid the groundwork for modern ethics. Kant's ideas influenced a wide range of fields, including political theory and the philosophy of science, establishing him as a central figure of the Enlightenment.